It is true that according to research the genes that affect energy balance in the body effectively promote energy intake and weight gain but are inefficient to promote energy expenditure and weight loss. This is because it is likely to be a polygenic condition such that there are numerous genes in interaction. Therefore the genes that promote energy intake and weight gain are insufficient to promote weight loss and energy expenditure which is the required energy to carry out physical activities such as breathing, exercising, etc.
Iron is a key component of hemoglobin. Hemoglobin the the protein responsible for transporting oxygen uses iron to bond oxygen. Additionally Hemoglobin is a key component of RBC (erythrocytes)... If iron is deficit the body is not able to produce red blood cells and it can result in iron deficient anemia.
